This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The microtubule-organizing center (MTOC) nucleates microtubules inside the cell. In yeast, the MTOC is called the spindle pole body (SPB). We have found that the Aurora kinase Ipl1 in yeast is required for SPB duplication and separation during meiosis. Meanwhile, the polo-like kinase Cdc5 plays a potential role in licensing SPB duplication. We plan to map phosphoresidues on the meiotic SPB by SPB phosphoproteome. This work could provide insights into the mechanism of protein phosphorylation by Ipl1 and Cdc5 in SPB dynamics during meiosis. Because these regulatory factors are conserved, and the yeast SPB is functionally equivalent to and shares structural components with the centrosome, this work will generate insights into the regulation of centrosome duplication and separation in vertebrate meiosis.